Very little progress today as other jobs were more urgent. I started by rectifying the seat width as stated in my earlier post, then it was time for this:



This cutter has been ground specifically for boring the throats of seats that we intend to modify. It's perfect as it does not leave any sharp edges at all, so blending the port into the seat becomes much easier later on. You can see here how much i've bored out of the middle, almost all of the bottom angle has disappeared:



Again, i used the dial gauge to ensure all of the seats were the same. This shows up some minor variation in the casting/original machining:



That's all for now, hopefully i'll get onto the exhaust side tomorrow.